MSR路由器配置DHCP跨网段下发ip地址

一、需求：

1、分支所有pc通过dhcp方式从总部核心自动获取ip地址与网关，实现统一管理；

2、总部与分支通过L2TP VPN方式建立隧道，实现内网互通；

二、问题描述：

1、分支pc无法从总部核心获取ip地址；

2、在分支开启debugging dhcp relay all发现如下信息：

fenzhi_sw DHCPR/7/PACKET: To 10.253.100.254 port 67, interface is selected by routing table Message type: REQUEST (1) Hardware type: 1, Hardware address length: 6 Hops: 1, Transaction ID: 4283335522 Seconds: 0, Broadcast flag: 1 Client IP address: 0.0.0.0 Your IP address: 0.0.0.0 Server IP address: 0.0.0.0 Relay agent IP address: 10.253.20.2 Client hardware address: 2a31-3cdb-0706 Server host name: not configured Boot file name: not configured DHCP message type: DHCPDISCOVER (1)

3、在总部开启debugging dhcp server all发现如下信息：

*Aug 7 16:29:29:646 2018 zongbu_sw DHCPS/7/EVENT: Receive a DHCPDISCOVER message from 10.253.20.2. *Aug 7 16:29:29:646 2018 zongbu_sw DHCPS/7/EVENT: No matching network for the client. *Aug 7 16:29:36:616 2018 zongbu_sw DHCPS/7/PACKET: From 10.253.20.2 port 67, interface Vlan-interface1000 Message type: REQUEST (1) Hardware type: 1, Hardware address length: 6 Hops: 1, Transaction ID: 4283335522 Seconds: 0, Broadcast flag: 1 Client IP address: 0.0.0.0 Your IP address: 0.0.0.0 Server IP address: 0.0.0.0 Relay agent IP address: 10.253.20.2 Client hardware address: 2a31-3cdb-0706 Server host name: not configured Boot file name: not configured DHCP message type: DHCPDISCOVER (1)